Silver halide photographic emulsions supersensitized with an oxadiazole and a methine dye

ABSTRACT

Photographic silver halide emulsions are supersensitized with the combination of a photographic spectral sensitizing methine dye and an oxazole, an oxadiazole, a thiozole or a thiadiazole.

United States Patent Inventor Dugald A. Brooks Rochester, N.Y.

Appl. No. 851,074

Filed Aug. 18, 1969 Patented Oct. 26, 1971 Assignee Eastman Kodak Company Rochester, N.Y.

Continuation-impart of application Ser. No. 757,148, Sept. 3, 1968, now abandoned.

SILVER HALIDE PHOTOGRAPHIC EMULSIONS SUPERSENSITIZED WITH AN OXADIAZOLE AND A METHINE DYE [56] References Cited UNITED STATES PATENTS 2,271,623 2/1942 96/104 2,398,778 4/1946 96/104 2,411,546 11/1946 Knott 96/104 2,848,329 8/1958 Chechak et a1. 96/104 3,017,270 1/1962 Tregillus et a1. 96/109 3,113,026 12/1963 Sprung 96/109 3,397,987 8/1968 Luckey et al. 96/109 3,457,078 7/1969 Riester 96/104 FOREIGN PATENTS 861,907 3/1961 Great Britain 96/104 Primary Examiner-.1. Travis Brown Attorneys-Ogden H. Webster, .1. R. Frederick and W. H. .1.

Kline ABSTRACT: Photographic silver halide emulsions are supersensitized with the combination of a photographic spectral sensitizing methine dye and an oxazole, an oxadiazole, a thiozole or a thiadiazole.

SILVER HALIDE PHOTOGRAPHIC EMULSIONS SUPERSENSITIZED WITH AN OXADIAZOLE AND A METHINE DYE or a nitrogen atom; R represents a lower alkyl group containing from one to four carbon atoms, e.g., methyl, ethyl, isopropyl, butyl, benzyl, phenethyl, etc., an aryl group, e.g., phenyl, tolyl, chlorophenyl, methoxyphenyl, naphthyl, stilbe- This application is a continuation-in-part of applicant 5 nyl, etc., an amino group including substituted amino, e.g., pending application Ser. No. 757,148 filed Sept. 3, 1968. now amino, methylamino, diethylamino, butylamino, phenabandoned. ylamino, diphenylamino, naphthylamino, anisidino, anilino,

This invention relates to novel photographic silver halide acetamidophenylsulfonamino, etc., styryl; amido groups such emulsions containing a new supersensitizing combination. as acetamido or a halogen substituent, e.g., chlorine or It is well known in the photographic art that certain methine bromine; R represents a hydrogen atom or a value given for dyes extend the spectral sensitivity of photographic emulsions. R Compounds embraced by Formula 1 above include the It is further known that a number of such dyes in combination various oxazoles, thiazoles, oxadiazoles, thiadizazoles, and the with each other or with certain other compounds markedly li alter the sensitivity of photographic emulsions, for example in Typical heterocyclic compounds of the invention relative speed, compared with the individual dyes by them- 1 represented by Formula 1 above include those listed in the folselves in such emulsions, While supersensitizing combinations lowing Table of the above kind have been proposed for various uses, only a TABLE] relatively few have proven entirely satisfactory for commercial photographic applications. Consequently, there is still need in the art for improved supersensitizing combinations comprising methine dyes. g

. 0. Compound It is, accordingly, an ob ect of this invention to provide a new class of supersensitizing combinations for photographic silver halide emulsions.

e yl-S-(u-naphthyD-l,3,4-oxadiazole 1 Another ob ect of this invention IS to provide novel emulm 2Mmy| 5 p.hydmypheny| 1JMxadiuole sions containing such new supersensitizing combinations and IV 2,5-Di(p-aminophenyl)-l,3,4-oxadiazole photographic elements prepared therewith. 2= Y Y' s-7: 2a I pt oxyp eny -me y- -oxa iiizoe Other ob ects of the invent on will be apparent from this disv" z (p mphcnyl) s phcnyl I Mmadiuole closure and the appended claims Vlll 5-Phenyl-2stilben-4 yl-I,3,4-oxadiazole l have now made the important discovery that new and im- IX t y p y )-I. .4- n i zol proved supersensitizing combinations for light-sensitive x F '?"f'= h t hic silver halide emulsions are reduced with (l) a P o 8 P XlIl Z-Anilino-S-phenyl-l,3,4-thiadia:ole heterocyclic compound selected from the group consisting of my 2.( .A [amido henyl ulfo ami q) 5.meghy| 1 3 4. an oxazole, an oxadiazole, a thiazole or a thiadiazole, and (2) X 2 lhiadiazzle d 1 V -Acetami o-5-iodo-l,3,4-thia iazoe a photogfaphlc spec.tral.sensnlzm.g w f The new.su XVl 2-(p-anisidino)-5-methyl-I,3,4-thiadiazole persensitizing combinations of this invention are compatible xv" 4.Bi [2-(shenyloxalolyl)lbenzene with the emulsions giving essentially clear layers with excel- XVlll 2,S-Diphenyloxazole lent keeping stability and causing relatively little or no fogging XIX -ff v y l -p v in both fresh and incubated condition. XX Z-Anllino-4,5-dlphenyloxazole f d heteroc clic com ounds of above com- 40 lMISIHs'pmylomolyl)Mm The P ene y p XXll 2-(p-Aminophenyl)-4-methylthiazole ponent l are represented by the following formula: I. xxiii 2-Anilino-4-phenylthiazole XXlV 2,5-Diphenylthiazole /Ai E The above class of heterocyclic compounds are well known and methods for their preparations are described in the prior art literature. Some of the more 5 ecific references are in- N P f cluded herein for illustrative purposes, for example, reference A1 mm f' B can be had to Chemical Abstracts 29, 5444*; 30, 4837; 32, represents a methine group, e.g.,=CH-, and substituted 5 3 32, 5573; 44 251611,. 49, l011d;49 7560b; 50 64350,. gmupsmh as 51, P1298312; 51, l3580a; 53, 78008, 53, 15064h; s4, isioo 55, l8297c; 59, 630f; etc. =0- and The methine dyes of above component (2) of the invention 9H zHi are represented by the following formulas:

"Z2 R1-N(CH=CH) n 1C=L(-L=L)m C(=CHOH). 1=IIIR;

O=(I3 N R R1N(CH=CH),. C=LL=C C=LC(=CHCH)a i=lIVR:

Di X

i -Qh R1'N(CH=CH) n-i-C=LL=C-C=O iN(-CH=CH) u-iC=L(|3=L (-L=L) -1 C (=CHCH) d-1=NR1 -C I o-o "Q2" and TABLE 2 Dye No. Cyanine Spectral Sensitizer Dyes A 1,1'-Diethyl-2,Z'-cyanine iodide B 3,3'-Dimethyl-9-ethyl-4:5,4':5-

naphthothiacarbocyanine chloride C 3,3'-Di-fi-hydroxyethylthiadicarbocyanine bromide D l-Butyl-3-ethyl-4 phenylthia-4-car1:ocyanine iodide E 3,3'-Diethyloxathiadicarbocyanine iodide F l,3-Diethyl-5-[di( l-ethyl-2( 1H H1- naphthothiazolylidene)-isopropylidene] barbituric acid -[Di( l-ethyl-2( IH l-finaphthothiazolylidene)isopropylidene]-l ,3 indandione ,3-Diethyl-5-[( lelhyl-2( 1H Hinaphthothiazolylidenej-isopropylidene] barbituric acid l-Ethyl-2( lH)-B- naphthiazolylidcne)isopropylidene- 1,3- ind-andione -fDi(l-ethyl-2(1H)-finaphthothiazolylidene)isopropylidenell,3-di(l3- methoxyethyUburbituric acid [(Z-benzothiazolylethiodide)methylenel-Z-B- methoxyethyl- 5-[( l-methyl-2( 1H )naphthol 1.2]thiazolylidene-B-phcnyl-ethylidene] -4- thiazolidone .a-nleih l-s-lr l ,3-di(3cthyl 2(3H)- benzoxazolylidene)-ethylidene] indan-Z-ylidene} barbituric acid -Dicyanomethylene-1,3di[(3-ethyl-2(3H bcnzothiazolylidene)ethylidenee indan ,s-oieih l-s-la 3-=ih l-2 3H benzothiazolylidene )-u *l l 3-ethyl-2 (3H )benzothiazolylidene)amino] -ethy1idene} barbituric acid ,3-Diethy1-5-{2,5-di[(3-ethyl-2(3H)- benzoxazolylidene)-ethylidene] cyclopentylidcne} barbituric acid P Anhydro-Lethyl-S-phenyl-1'-(4-sulfohutyl)thiu-4'- carbocyanine hydroxide l,3-Diethyl-5-{2-( 3-ethyl-2( 3H benzothiazolylidenel- 5-[(3-ethyl-2( 3H benzothiazolylidene )ethylidenee -cyclopentylidenel barbituric acid R 5-|Di(3ethyl-2(3H benzothiazolylidene)isopropylidene- 3-ethyl-lphenyl hydantoin S 5-lDi(3-ethyl-2(3H)- benzothiazolylidene)isopropylidene- 2,2- dimethyl- I ,3-dioxane-4,6-dione T 2-[(2-Benzothiazolylethoperchlorate)methylenel-3-( 3-dimethylaminopropyl)-S-[(l-methylnaphthol1,2 dl-thiazolin- 2-ylidene)-l-phenylethylidenel-4- thiazolidinone U 3-(3-Dimethylaminopropyl)-5-[(3-ethyl-2- benzothiazolinylidene)ethylidenel -2-thio-2,4- oxazolidinedionc V 3,3 '-Diethylselenadicarboeyaninc iodide The methine dyes of the invention illustrated by those listed in above Table 2 have been previously described in the literature, except for Dye No. K which forms part of and is illustrative of the subject matter of copending application of D. W. Heseltine, Ser. No. 463,024, filed June 10, 1965, now U.S.

Pat. No. 3,440,052. Pertinent references include the follow- Brooker U.S. Pat. No. 2,177,403, issued 10/24/39 Carroll et a1. U.S. Pat. No. 2,177,635, issued 10/31/39 Carroll U.S. Pat. No, 2,206,076, issued 7/2/40 Brooker U.S. Pat. No. 2,211,762, issued 8/20/40 Brooker et al. U.S. Pat. No. 2,213,238, issued 9/3/40 Brooker U.S. Pat. No. 2,307,916, issued 1/12/43 Brooker et. al. U.S. Pat. No. 2,313,922, issued 3/16/43 Schneider U.S. Pat. No. 2,374,505, issued 4/24/45 Falleson et al. U.S. Pat. No. 2,378,917, issued 6/26/45 Brooker U.S. Pat. No. 2,454,629, issued 1/23/48 Thompson U.S. Pat. No. 2,535,993, issued 12/26/50 Carroll et a1. U.S. Pat. No. 2,950,196, issued 8/23/60 Brooker et al. U.S. Pat. No. 2,955,939, issued 10/11/60 .lones U.S. Pat. No. 2,961,318, issued 11/22/60 Brooker et al. U.S. Pat. No. 3,194,805, issued 7/13/65 Tabor et al. U.S. Pat. No. 3,335,010, issued 8/8/67 Brooker et al. U.S. Re. No. 24,292, reissued 3/19/571.G., Br. Pat. No. 434,235, accepted 8/28/35 The following example describes the preparation of above mentioned Dye No. S.

5-[Bis(3-ethyl-Z-benzothlazollnylldene)is0pr0py1ldene]2,2-dimethy1-1, 3-dioxaue-4, 6-di0ne A mixture of 3-ethyl-2-ethylmer manner well known to those skilled in the art by measuring the sensitivity of a series of test portions of the same emulsion, each portion containing a different concentration of the sensitizing dye. In general, the heterocyclic compounds in my invention have little or no sensitizing action by themselves alone in the emulsions employed.

Ordinarily, the optimum or near optimum concentration of the cyanine dyes herein is of the order of from 0.01 to 1.2 g. per mole of silver halide in the emulsion, and that of the heterocyclic compound herein is of the order of from 0.05 to 5,0 g.

The methods of incorporating sensitizing dyes in silver halide emulsions are well known to those skilled in the art and these known techniques are employed in dispersing the dyes of the invention in the emulsions. 1n practicing my invention the sensitizing dyes and the heterocyclic compounds can be directly dispersed in the emulsions, or they can first be dissolved in some convenient solvent, such as pyridine, methyl alcohol, acetone, etc. (or mixtures or such solvents), or diluted with water in some instances, and added to the emulsions in the form of these solutions. If desired, the components can be separately dissolved in a given solvent and added separately to the emulsion, or they can be dissolved in the same or different solvent and these solutions mixed together before addition is made to the silver halide emulsions. The dyes and heterocyclic compounds of the invention are dispersed in the finished emulsions in such manner as to be uniformly distributed throughout the emulsions prior to coating on a suitable support, such as paper, glass, cellulose ester film, polyvinyl resin film (e.g., polystyrene film, polyvinyl chloride film, etc.) polyester film, etc. The following procedure has been found quite satisfactory: Stock solutions of the heterocyclic compounds of Formula I and the dyes of Formulas 11 to V above are prepared by separately dissolving these components in appropriate solvents as described above. Then, to the flowable silver halide emulsion, the desired amount of stock solution of one of the dyes is slowly added while stirring the emulsion. Stirring is continued until the dye is thoroughly incorporated in the emulsion. Then, the desired amount of stock solution of one of the heterocyclic compounds is slowly added to the emulsion while stirring. Stirring is continued until the added materials are thoroughly incorporated in the emulsion. The

supersensitized emulsions can then be coated on a suitable support and the coating allowed to dry. In some instances, it may be desirable to heat the supersensitized emulsion for a few minutes before coating onto the suitable support. The details of such coating techniques are well known to those skilled in the art. The foregoing procedure and proportions are to be regarded only as illustrative. Clearly, the invention is directed to any silver halide emulsion containing a supersensitizing combination of the invention, e.g., gelatino-silver chloride, -chlorobromide, -chloroiodide, -chlorobromoiodide, -bromoiodide, etc., emulsions Fine grain emulsions can also be employed herein. These may be prepared by precipitating photosensitive silver halide crystals, in an aqueous medium, in the presence of an acid substituted aryl mercaptan, e.g., thiosalicylic acid, dissolved in said medium. Gelatin or other suitable hydrophilic colloid is added and the emulsion obtained is chilled and set. The chilled emulsion is then shredded into small noodles and washed in running tap water. After washing, the emulsion is remelted, and the volume, pH and Pag are adjusted. A fine grain gelatino-silver bromoiodide emulsion prepared in the above manner and containing a dye combination of the invention is particularly useful for recording radiations in the region of the spectrum ranging about from 300 to 750 nm. in fine detail. Further details for preparing such fine grain emulsions can be had by reference to copending application of Sutherns, Ser. No. 622,034, filed Mar. l0, 1967, now U.S. Pat. No. 3,519,427.

The emulsions of this invention can contain the chemical sensitizers, speed increasing compounds, plasticizers, hardeners and coating aids, and the silver halide may be dispersed in any of the binders, that are described and referred I to in Graham et al. U.S. Pat. No. 3,046,129 issued July 24, F

The following examples are included for a further understanding of the invention.

Examples 1 to These examples illustrate the supersensitization produced 3 To different portions of the same bai'ii'rMiiiigimd silver bromoiodide emulsion, containing 0.77 mole percent iodide, of the type described by Trivelli and Smith PhotJournal, 79, 3 (1939), are added the individual cyanine dyes and the heterocyclic compounds in the proportions given in table 3 hereinafter. In each case, after being digested at about C. for 10 minutes, the emulsion is coated at a coverage of 432 mg. silver per square foot on a cellulose acetate film support. A sample of each coating is exposed on an Eastman 1B Sensitometer to light from a tungsten source modulated by a stepwedge and Kodak Wratten No. 16 filter and processed-for 3 minutes in Kodak Developer D-l9 which has the following composition:

N methyl-p-aminophenol sulfate. 2.0 g.

Hydroquinone 8.0 g. Sodium sulfite (desiccated) 90.0 g. Sodium carbonate (monohydrate) 52.5 g. Potassium bromide 5.0 3.

Water to make [.0 liter results are listed in the following table together with the values for gamma and fog.

TABLE 3 supersensitization by 1, 3, 4-oxadiazoles (Addendum) Dye N o. and Addendum and Relaconc. (g./m01e cone. (g./mole tive Ex. N 0. silver) silver) speed -y Fog V (.04) None 100 0. 92 04 V (.04) I 660) 132 0. 90 04 V (.04) II 660) 126 0. 04 V (.04) III 660) 138 0. 04 I (.033) None .04 J (.033) III (.660) 79,500 1.10 .05 U (.060) None 1 2.10 .05 U (.060) IV (1.1) 261 1.82 .04 U (.060) VI (1.62) 126 1. 84 .04 A (.090) None 100 1.20 .06 A (.090) IV (1.1) 138 1.02 .05 A (.090) V (1.3) 132 0.86 .09 J (.076) None 100 .06 J (.076) IV (1.1) 135,000 1 18 .06 J (.076) V (1 3) 9,330 0 97 .15 .T (.076) VI (1 6) 3,980 1 53 .06 N (.076) None 100 1 12 .04 N (.076) IV (.660) 148 1 22 .04 F (.076) None 00 100 .07 F (.076) IV 660) 1,070 1.45 .06 L (.033) None 1 1. 56 05 L (.0 IV (.660) 776 1.56 .04 L (.033) IX (.660) 1,410 1.28 .06 D (.090) None 1 a 0.85 .04 D (.090) V (1.3) 219 0.71 .04 G (.076) None 100 1. 42 .05 G (.076) V (.330) 13,800 0. 63 .40 H (.076) None 100 04 H (.076) V (330) 1,260 0. 74 .46 I (.076) None 100 0. 92 06 I (.076) V (.330) 1,150 0. 75 .60 Q (.076) None 100 l. 70 .04 Q (.076) V (.330) 575 1.31 .06 O (.076) None 100 1.80 .04 O (.076) -V (.330) 977 1.06 17 S (.076) None 100 1. 70 04 S (.076) V (.330) 151 0.87 .33 R (.076) None 100 1. 37 03 R (.076) V (.330) 267 1. 20 04 B (.090) None 100 1 46 .06 B (.090) V1 (1.6) 1 16 .07 J' (.076) None 100 .06 J (.076) VII (3.0) 550 1. 20 06 J (.076) VIII (.560) 4, 360 1.28 .06 J (.076) IX (.660) 2,140 1.10 .07 M (.033) None 100 .04 M (.033) IX (.660) 276 1 52 .04 K (.066) None 100 1 27 .06 K (.066) X (2.0) 219 1 15 .06

Referring to above table 3, it will be seen that the relative speed for each of the supersensitizing combinations is markedly greater than that of the same emulsion containing the specified dye but containing no 1,3,4-oxadiazole addendum. Remarkably high relative speeds are shown for examples 2B, 5B, 5C, SD, 10B, 18C and 18D with no increase in fog in most instances.

Examples 2l to 25 TABLE 4 supersensitization by 1. 3, 4-thladlazoles (Addendum) Dye No. and Addendum and Relaconc. (gJmole cone. (g./mole tive silver) silver) speed 7 Fog J (.076) None 100 .06 J (.076) XII (.660) 49,000 1. 73 .05 V 040) None 100 0.80 .04 V (.040) XIII (.660) 145 0.74 .04 D 076) None 100 0. 93 04 D 076) XII (.660) 126 0. 90 04 K 053) None 100 1. 41 04 K (.053) XVI (.660) 1. 27 04 J (.076) None 100 .05 .T 076) XIV (.660) 832 1. 66 04 J (.076) XV (.165) 224 1.80 .06 J 076) XVI 660) 7, 950 1 40 04 lt will be noted from above table 4 that in each instance substantial improvement in relative speed over each dye alone is shown witli the supersensitizing Combinations of the invention.

Examples 26-34 TABLE supersensitization by oxazoles (Addendum) Dye No. and Addendum and Relaconc. (g./mole cone. (g./mole tive silver) silver) speed 7 Fog C (.050) None 100 1.65 .04 C (.050) XVII (.330) 204 1.65 .04 V (.040) None 100 0.80 .04 V (.040) XVII (.330) 141 1.25 .03 D (.076) None 100 0.93 .04 D 076) XVII (.330) 159 1.40 .04 D (.076) XVIII (.330) 174 0.82 .04 .l' (.076) None 100 .05 J (.076) XVIII (.330) 380 1.93 .05 J (.076) XXI (.330) 2,000 2.20 .04 V (.040) None 100 0. 94 .04 V (.040) XXI (.330) 135 1.00 .04 V (.040) XX (.660) 302 0.96 .04 D (.076) None 100 0.83 .04 D (.076) XXI (.330) 436 0.65 .04 D (.076) XX (.660) 457 0.68 .04 K (.053) None 100 1.21 .05 K (.053) XXI (.330) 186 1.11 .05 K (.053) XX (.660) 178 0.85 .04 J (.076) N 100 1.32 .06 J (.076) XX (.660) 302 1.26 .05 E (.053) None 100 0.96 .04 E (.053) XXI (.990) 209 1.23 .04

- defined by Formula I above show substantial improvements in relative speed in each instance as compared with that shown for the individual dye alone in the same emulsion.

TABLE 6 supersensitization by thiazoles (Addendum) Dye No. and Addendum and Relaconc. (g./rnole cone. (gJmole tlve silver) silver) speed '7 Fog P 076) None 100 0. 7 04 P 076) XXII 330) 269 0.92 04 J 076) None 100 1. 70 06 .I 076) XXIII 660) 372 1. 86 06 J 076) XXIV 660) 2, 400 1. 58 07 P 053) None 100 1. 04 P 053) XXIII (.660) 126 1. 38 04 P 053) XXIV 660) 145 1. 37 05 K 053) None 100 1. 34 05 K 053) XXIII 660) 126 1. 33 05 C 050) None 100 1. 43 05 C 050) XXIV 660) 129 1. 53 05 V (.040) None 100 l. 34 .05 V 040) XXIV 660) 276 1. 24 04 Referring to above table 6, it will be noted that in each instance substantial improvement in relative speed over each dye alone is shown by the super-sensitizing combinations of the invention.

It will be apparent from all of the foregoing that still other valuable supersensitizing combinations of the invention can be produced by selecting other heterocylic compounds embraced by Formula l above and other cyanine dyes embraced by Formulas ll to V1 above, and that such combinations likewise will give desirably improved supersensitized photographic silver halide emulsions and elements.

The invention has been described in detail with particular reference to preferred embodiments thereof, but, it will be understood that variations and modifications can be effected within the spirit and scope of the invention described hereinabove and in the appended claims.

We claim:

1. A photographic silver halide emulsion containing a supersensitizing combination of (l) a heterocyclic compound represented by the following formula:

Examples 35-40 These examples illustrate the supersensitization produced with the thiazoles defined by Formula I above in combinations with various cyani ne dyes coming under the definitions offerrnfiTas ll to VI above. The testing procedure is exactly the same as that described in above examples 1 to 20 and the results are tabulated in table 6 in the same manner.

- ethyl-4-phenylthia-4'-carbocyanine represents a member selected from the group consisting of a hydrogen atom and a value given for R X represents an acid D represeni'irfifiifi selected from the group consisting of an oxygen atom, a sulfur atom and the nonmetallic atoms necessary to complete a diazole ring; W represents the nonmetallic atoms necessary to complete a ring selected from the group consisting of a cyclopentene ring, a cyclohexene ring and an indan ring; Z and Z represents the nonmetallic atoms necessary to complete a nitrogen containing heterocyclic nucleus of the type used in methine dyes containing from five to six atoms in the heterocyclic ring; and Q -and Q each represents the nonmetallic atoms necessary to complete a heterocyclic ketomethylene nucleus of the type used in merocyanine dyes containing from five to six atoms in the heterocyclic ring.

2. A light sensitive photographic silver halide emulsion containing a supersensitizing combination comprising (1) at least one compound selected from the group consisting of 2- methyl-S-phenyll ,3 ,4-oxadiazole; 2-methyl-5-( a-naphthyl)- l,3 ,4-oxadiazole; 2-methyl-5-p-hydroxyphenyl-l ,3 ,4-oxadiazole; 2,5-di-(p-aminophenyl)-1,3,4-oxadiazole; 2,5-di(paminostyryl)-1,3,4-oxadiazole; 5-(p-ethoxyphenyl)-2-methyl- 1,3,4-oxadiazole; 2-(p-biphenyl)-5-phenyl-l ,3,4-oxadiazole; 5-phenyl-2-stilben-4-yl-l ,3,4-oxadiazole; 2,5-bis( 4- diethylaminophenyl)-l,3,4-oxadiazole; 2,5-di-(a-naphthyl)- 1,3,4-oxadiazole; and (2) at least one methine dye selected from the group consisting of 1,1'-diethyl-2,2'-cyanine salt; 3,3'-dimethyl-9-ethyl-4,5,4',5'-naphthothiacarbocyanine salt; 3,3-di-B-hydroxyethylthiadicarbocyanine salt; 1-butyl-3- salt; 3,3-diethylxathiadicarbocyanine salt; l,3-diethyl--[di( l-ethyl-2( 1H )-,B- naphthothiazolylidene)isopropylidene]barbituric acid; 2-

[di( l-ethyl-2( lH)-fl-naphthothiazolylidene)isopropylidene1- l,3-indiandione; l,3-diethyl- 5-[(l-ethyl-2(1H)-B- naphthothiazolylidene)isopropylidene]-barbituric acid; 2-[(l -ethyl-2( 1 H )-,l3-naphthothiazolylidene)isopropylidene]-l ,3-

indandione; 5-[di( l-ethyl-2( lH)-B-naphthothiazolylidene)isopropylidene]-1,3-di(-methoxyethyl)barbituric acid; 2-[(2-benzothiazolylethiodide)methylene 3-B-methoxyethyl-5-[( l-methyl- 2( lH)-naphtho '[l,2]thiazolylidene-aphenylethylidene1- 4- thiazolidone; 1,3-diethyl-5- [l,3-di(3- ethyl-2(3H)-benzoxazolyli-dene)-ethylidene]indan-2-ylidene barbituric acid; 2-dicyanomethylene-l,3-di[(3-ethyl-2(3H)- benzothiazolylidene)ethylideneg8indan; ethyl-2( 3H )-benzothiazolylidene) -a-[ 3-ethyl- 2( 3H benzothiazolylidene)amino]ethylidene barbituric acid; 1,3- diethyl-S 2,5-di[(3-ethyl-2(3H)-benzoxazolylidene)ethylidene]-cyclopentylidene barbituric acid; anhydro-3-ethyl-5- phenyl-l '-(4-sulfobutyl)thia-4-carbocyanine hydroxide; 1,3- diethyl-S- 2-(3-ethyl-2(3H)-benzothiazolylidene)-5-[(3- ethyl-2(3H)-benzothiazolylidene)ethylidene]cyclopentylidene barbituric acid; 5-[di(3-ethyl-2(3H)-benzothiazolylidene)isopropylidene]-3-ethyl-l-phenyl hydantoin; 5-[di(3- ethyl-2(3H)-benzothiazolylidene)isopropylidene]-2,2- dimethyl-l ,3-dioxane-4,6-dione; benzothiazolylethoperchlorate)methylene1-3-(3- dimethylaminopropyl)-5-[( l-methylnaphtho[ l ,2d]thiazolin- 2-ylidene)-l-phenylethylidene]-4-thiazolidinone; 3-(3- dimethylaminopropyl)-5-[(3-ethyl-2-benzothiazolinylidene)ethylidene]-2-thio-2,4-oxazolidinedione; and 3,3 diethylselenadicarbocyanine salt.

3. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(paminophenyl)-1,3,4-oxadiazole and (2) 5-[di(l-ethyl-2(lH)- B-naphthothiazolylidene )isopropylidene l ,3-di(B-methoxyethyl)barbituric acid.

4. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(paminostyryl)-1,3,4-oxadiazole and (2) 2-[di( l-ethyl-2(ll-l)-finaphthothiazolylidene)isopropylidene1-l ,3-indandione.

5. A light-sensitvive photographic silver halide emulsion supersensitized with combination combination (I) (l) 2,5-di(paminophenyl)-1,3,4-oxadiazole (2) (3) 1,1 -diethyl-2,2- cyanine salt.

6. A light-sensitive photographic silver halide emulsion supersensitized with the combinition comprising (1) 2,5 -di(paminostyryl)-l,3,4-oxadiazole and (2) 2-[(l-ethyl-2(lH)-B- naphthiazolylidene )isopropylidene-l ,3-indandione.

7. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(paminostyryl)-l,3,4-oxadiazole and (2) 1,3-diethyl-5- [2-(3- ethyl- 2(3H)-benzothiazolylidene)-5-[(3-ethyl-2(3H)- benzothiazolylidene)ethylideneg8cyclopentylidene} barbituric acid.

8. A photographic element comprising a support having a coating thereon containing an emulsion of claim 1.

9. A photographic element comprising a support having a coating thereon containing an emulsion of claim 2. 

2. A light sensitive photographic silver halide emulsion containing a supersensitizing combination comprising (1) at least one compound selected from the group consisting of 2-methyl-5-phenyl-1,3,4-oxadiazole; 2-methyl-5-( Alpha -naphthyl)-1,3,4-oxadiazole; 2-methyl-5-p-hydroxyphenyl-1,3,4-oxadiazole; 2,5-di-(p-aminophenyl)-1,3,4-oxadiazole; 2,5-di(p-aminostyryl)-1,3,4-oxadiazole; 5-(p-ethoxyphenyl)-2-methyl-1,3,4-oxadiazole; 2-(p-biphenyl)-5-phenyl-1,3,4-oxadiazole; 5-phenyl-2-stilben-4-yl-1,3, 4-oxadiazole; 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; 2, 5-di-( Alpha -naphthyl)-1,3,4-oxadiazole; and (2) at least one methine dye selected from the group consisting of 1,1''-diethyl-2, 2''-cyanine salt; 3,3''-dimethyl-9-ethyl-4,5,4'',5''-naphthothiacarbocyanine salt; 3,3''-di- Beta -hydroxyethylthiadicarbocyanine salt; 1''-butyl-3-ethyl-4-phenylthia-4''-carbocyanine salt; 3,3''-diethyloxathiadicarbocyanine salt; 1,3-diethyl-5-(di(1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)barbituric acid; 2-(di(1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)-1,3-indiandione; 1,3-diethyl- 5-((1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)-barbituric acid; 2-((1-ethyl-2(1H)- Beta -naphthiazolylidene)iso-propylidene)-1,3-indandione; 5-(di(1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)-1,3-di(-methoxyethyl)barbituric acid; 2-((2-benzothiazolylethiodide)methylene )- 3- Beta -methoxyethyl-5-((1-methyl- 2(1H)-naphtho (1,2)thiazolylidene- Alpha -phenylethylidene)- 4-thiazolidone; 1,3-diethyl-5- (1,3-di(3-ethyl-2(3H)-benzoxazolyli-dene)-ethylidene)indan-2-ylidene barbituric acid; 2-dicyanomethylene-1,3-di((3-ethyl-2(3H) -benzothiazolylidene)ethylidene)indan; 1,3-diethyl-5- Beta -(3-ethyl-2(3H)-benzothiazolylidene) - Alpha -((3-ethyl- 2(3H)-benzothiazolylidene)amino)ethylidene barbituric acid; 1,3-diethyl-5 2,5-di((3-ethyl-2(3H)-benzoxazolylidene)ethylidene)-cyclopentylidene barbituric acid; anhydro-3-ethyl-5-phenyl-1''-(4-sulfobutyl)thia-4''-carbocyanine hydroxide; 1,3-diethyl-5- 2-(3-ethyl-2(3H)-benzothiazolylidene)-5-((3-ethyl-2(3H) -benzothiazolylidene)ethylidene)cyclopentylidene barbituric acid; 5-(di(3-ethyl-2(3H)-benzothiazolylidene)isopropylidene)-3-ethyl-1-phenyl hydantoin; 5-(di(3-ethyl-2(3H)-benzothiazolylidene)isopropylidene)-2,2-dimethyl-1,3 -dioxane-4,6-dione; 2-((2-benzothiazolylethoperchlorate)methylene)-3-(3-dimethylaminopropyl)-5 -((1-methylnaphtho(1,2d)thiazolin-2-ylidene)-1-phenylethylidene)-4 -thiazolidinone; 3-(3-dimethylaminopropyl)-5-((3-ethyl-2-benzothiazolinylidene)ethylidene)-2 -thio-2,4-oxazolidinedione; and 3,3''-diethylselenadicarbocyanine salt.
 3. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(p-aminophenyl)-1,3,4-oxadiazole and (2) 5-(di(1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)-1,3-di( Beta -methoxyethyl)barbituric acid.
 4. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(p-aminostyryl)-1,3,4-oxadiazole and (2) 2-(di(1-ethyl-2(1H)- Beta -naphthothiazolylidene)isopropylidene)-1,3-indandione.
 5. A light-sensitvive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(p-aminophenyl)-1,3,4-oxadiazole (2) 1,1''-diethyl-2,2''-cyanine salt.
 6. A light-sensitive photographic silver halide emulsion supersensitized with the combinition comprising (1) 2,5-di(p-aminostyryl)-1,3,4-oxadiazole and (2) 2-((1-ethyl-2(1H)- Beta -naphthiazolylidene)isopropylidene)-1,3-indandione.
 7. A light-sensitive photographic silver halide emulsion supersensitized with the combination comprising (1) 2,5-di(p-aminostyryl)-1,3,4-oxadiazole and (2) 1,3-diethyl-5- 2-(3-ethyl-2(3H)-benzothiazolylidene)-5-((3-ethyl-2(3H) -benzothiazolylidene)ethylidene)cyclopentylidene barbituric acid.
 8. A photographic element comprising a support having a coating thereon containing an emulsion of claim
 1. 9. A photographic element comprising a support having a coating thereon containing an emulsion of claim
 2. 